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NIC Teaming or seperate subnet?

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Okay so I’m trying to do some config changes to reduce network traffic between a few servers that seems to drag my entire LAN down.

the primary focus of this questions about setting up a pair of NICs. For this example, let’s say I have Server A, Server B, Primary Gigaswitch and an optional Backbone Gigaswitch.

So a massive data transfer like a backup runs over the network Pulling info from ServerB to ServerA over the Primary Gigaswitch. When this happens all users experience a significant slow down in the LAN. Both Servers are Win 2K3 and have a pair of identical Intel 100Pro GigaNICs. But only one is up and running right now.

My options are these:

– Team the NICs together. Use Network Load Balencing to share the bandwidth between two GigaNICs. Then setup a VLAN in the Primary GigaSwitch and remove unneccessary broadcast traffic. If you feel this is the best method how should the NICs be configured to work together? I can figure out the VLAN, but am not sure on the proper way to configure the NICs for best performance.

– Setup NICs on seperate subnets. Have the secondary NICs go to a Backbone GigaSwitch. Then use some sort of internal routing to ensure only traffic destined for another server on the backbone is routed through the secondary NIC. Or perhaps IP filtering to insure only certain ports go through the backbone, like the ports Veritas uses. Again, if you feel this is the best option how would you configure the NICs in this scenerio?

– Have two NICs both going to the primary Giga Switch and with IPs on the same subnet, but use VLAN to seperate traffic. Again, if this is the option you feel best how would you config the NICs?

None of these options cost me anything extra since I have all the parts inhouse. Just looking for the best option to allow LAN traffic to maintain high performance in the midst of massive data transfer between Servers A & B. And then of course how do I setup the NICs in that option.

Thanks,
Mike

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Sorry I lost track of my thoughts. Option three should be to use a crossover cable between servers. Similar to the second option, but without the backbone switch.

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you could schedule backups after hours or use 1 day full and then differential backups which would reduce the need for huge data transfers.

you don’t mention the backup schedules or types of backups you use.

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with gigabit connections and even 100 full duplex on the switches, you have to have a LOT of data from a LOT of users and servers moving around the network at the same time to bring the LAN throughput down. very large graphics files can do this but then scheduling such moves on off hours reduces the network bandwidth load.

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Well I didn’t want to bring the backup schedule into it as I was trying to keep the scope of the question managable. The problem is we have over seas offices and the network is in use pretty much 24 hours a day. Not to mention the sheer amount of data we are trying to backup is close to 400 GBs. it takes a while to move all that data and get it to tape. meanwhile my LAN and WAN are taking a hit. Just trying to focus on how to move that data without taking a hit to the user’s performance. But thank you for the suggestion.

Mike

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Initially you mentioned large data transfers from Server A to Server B. If server A is a different site from where server B is, ought to consider some topology changes. Since network performance is critical in any large network, might consider delegation of the backup to individual sites or consider a 3rd party online backup storage solution.

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Sorry I didn’t mention sites. Both servers are on the same site. But I’m just trying to focus on NIC config for this question. I’m just not sure what the best practices are for NIC teaming or even if NIC teaming is the best config for my situation. Perhaps a VLAN or totally seperate subnet is the answer. But I’m trying to focus this question on the NICs and not so much the backup typology.

Thanks for the reply though. I do appreciate the help.

Mike

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I’m just thinking outloud.
–The crossover cable would clearly Isolate your network traffic and backups from interfearing with each other. –If you where to try and Vlan the traffic the switches would still see the summ of traffic on both vlans plus the overhead of running the vlan. As for how to configure the nics Microsoft calls what you want to do “Multihomed” and doing a knowlegebase search yealded a bunch of potential problems as well as configuration information. Here is one I considered pertinant. http://support.microsoft.com/default.aspx?scid=kb;en-us;262397

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Good thought! You know I had read about Multihoming in my search for an answer. I actually read that very KB article. Here’s a sentence that tripped me up. “When two network adapters are present in a computer (multihomed), a default gateway should only be assigned to one of the network adapter’s TCP/IP properties.” I read that to mean the primary NIC gets the gateway and the secondary gets none. Which is good cause when every i try and set a gateway on the secondary Windows barks and frankly if I’m using a crossover or dummy switch, i’m not sure what to make the gateway anyways. So I tried setting the secondary NIC on it’s own subnet (192.168.22.X as oppsed to 192.168.2.X for my primary) and running the backup there. Veritas even has a way to specific which NIC to use, which I did. however when the backup started, data still flowed over the primary NIC and LAN performance took a hit. I didn’t add a route add statement to windows cause I just wasn’t sure how the packets would be routed and at the time I also wasn’t sure if this would interrupt users currently logged into the system. Any thoughts on that?

Thanks for posting the link, very insiteful.

Mike

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Since your not using the second gig nic in each system. to a seperate Cheap gig switch. Add another NIC to your backup solution so ALL of the backup reated traffic is off the Primary and the backbone switches.

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Again just to keep the convo going I’ve marked this unacceptable, but I think you’re onto something. Your thought is the same one I had. but some threads have said to set up the secondary NICs on a different subnet and not to use a gateway. I guess if the secondary NICs are using a crossover or cheap Gigaswitch I’m not exactly sure how the gateway and DNS should be configured.

Do I need to add a route table? So Windows knows if you are trying to reach this server go through this NIC, otherwise everything else uses the primary NIC. Never set anything like that up, so any advice or link there would be appreciated.

Thanks for taking time to help me out!

Mike

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Have you thought about “clustering” , if your hardware allows it ?
I don’t recommend the not well defined “teaming” thought .Same goes for the second choice , connection to a common pool , VLAN etc. not the solution .
Rudimentary clusters were like option 3 that you have mentioned . Connect the two idling NICS to each other . If you don’t want to spend money , nobody to access the servers throug this subnet use a cross cable like you said. Servers A and B should have to be configured to do their transfer from this new path . This is the simplest , best cost/performance method . I do not think you need a VLAN or any help to do configuration . You have to take care for not forming a ethernet “loop” between the servers A and B . For this you will have to either employ spanning tree protocol or use the new ethernet link with a different “clustering ” protocol .

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if possible to add a drawing or a schema on this forum , do so ! can be much better to help you .

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I’m rating this unacceptable just to keep the conversation going before closing the question. But I think you are getting closer to the core of my issue. I have never worked with clustering servers before and would be interested to hear the advantage in a situation like mine. As for option three I didn’t realize that’s how clusters worked. But my thinking was to route traffic destined from Server B to Server A(and visa versa) through these secondary NICs. To me that seems like the most cost effective way to split the traffic so communication between those servers doesn’t interupt the LAN/WAN. The configuration of this setup is actually what i feel i do need help with. Perhpas that seems like too simple a question for this forum. but if this is the route you suggest as the best it would be nice to see a write on how the NICs should be configured. I have found several things on the web and technet, but none of them have generated a config that does what I’ve described above. maybe there is a better link or maybe someone here knows this stuff like the back of their hand. just looking for some aid in that area.

Thanks again guys! I feel like we’re getting close to a solution.

Mike

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As a follow on to my previous answer.
on the newly added nic you do not need a gateway or DNS configuration at all. The (new) NIC’s should be on the same subnet eliminating the need for the Gateway and you should be referenceing the other server by IP address not by domain name which eliminates the need for DNS. If your backup requests the IP address from DNS it will get the main IP address from the DNS Server.

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Thanks again chris.

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ok 007 , I mena buschman ! Since you rejected my answer and you seem a liitle bit far from “clustering ” I will answer more towards using your 2 idling NICs . But let me emphisize that you are MISSING one detail . And that is only defining a link with a better bandwith doesn’t mean the end of the new configuration . This big data transfer must be between some sort of a client server application , or app server – database server sort of configuration . Therefore , for better performance ( to separate other traffic from server-server traffic ) you have to do 2 things :
1. As it seems the best cost/performance option enable the the two NICs and force them to Fullduplex Gigabit through their configuration setup. Use a different subnet ip theme . You don’t have to use a switch , cable speed is ok . Use a cross cable . If this cable speed itself is not enough put 2 more NICs and use aggregation to configure it as one link between the servers .
2. You have to tell your servers about this link . That is not difficult . A new tcp ip definition . No gateway use dns/wins whatever you like . But if you define/map the disks of eah other’s or from inside the database servers define a new link pointing to the other servers disk this would couple up the performance . Otherwise the servers would try to estimate from which NIC to find the other server and get path confused .

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very hlpful advice. I think we are on the right track.

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Okay I went ahead and created a visio of my current config. I hope this helps you all visualize my predicament. User access the network 24 hours a day. So no Veritas reconfig is gonna help. I need to find the most efficent way to reduce lag on the LAN when a backup starts.

Here is a jpg of the layout:
http://mywebpages.comcast.net/buschman_007/Network/NICconfig01.jpg

Visio2K3 version:
http://mywebpages.comcast.net/buschman_007/Network/NICconfig01.vsd

Visio2K2 version:
http://mywebpages.comcast.net/buschman_007/Network/NICconfig01_2k2.jpg

Thanks guys,
Mike

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ok this answer will require a VERY LONG detail of an answer I will be glad to offer a very good solution just email me at wroming@harding-group.com and we will converse. There are several ways you can do it and will require some in depth questioning to give a proper answer.

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Thanks for the offer. I plan to get in contact, just some bigger fish have popped up in the meantime.

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